Zero volume air tube and method of making



July 18, 1961 H. E. BOWERMAN 2,992,955

ZERO VOLUME AIR TUBE AND METHOD OF MAKING Filed Jan. 13, 1958 5Sheets-Sheet 1 F/G. //l /4 7 74 9 FIG. V

IN VEN TOR.

HUZIE E. BOWERMIAN /WW9 ATTOR a? July 18, 1961 BOWERMAN 2,992,955

ZERO VOLUME AIR TUBE AND METHOD OF MAKING Filed Jan. 15, 1958 3Sheets-Sheet 2 FIG. X//

FIG. X/l/ u y 1961 H. E. BOWERMAN 2 992,955

ZERO VOLUME AIR TUBE AND METHOD OF MAKING Filed Jan. 15, 1958 5Sheets-Sheet 5 awmm FIG. Xl/l/ 3/ INVENTOR.

HULIE E BOWERMAN United States Patent G 2,992,955 ZERO VOLUME AIR TUBEAND METHOD OF MAKING Hulie E. Bowerman, 904 Meadow Oaks, Arlington, Tex.Filed Jan. 13, 1958, Ser. No. 708,615 Claims. (Cl. 154-85) Thisinvention relates to fluid actuated flexible sectioned tubes forclutches and brakes of the ring or disk type, the invention residingprincipally in the provision of such tubes of substantially zero volumeof interior cavity. when in the closed or unactivated position andcorrespondingly of lower volume than other tubes heretofore provided.These tubes may be used in conventional clutch and brake mechanisms notshown, or when maximum stroke tubes are required these conventionalmechanisms need be modified only to accommodate the correspondinglyenlarged flex sections of my tubes as will be readily perceived by thoseskilled in the art.

A primary object of this invention is thus seen to be to provide animproved flexible inflatable tube having an elongated cross sectionwhich will operate from a sub stantially zero air volume at its initialposition and yet which will withstand a considerable unit pressureduring operation.

A further object is to provide an inflatable tube of the type describedwherein the circular ends of the tube cross section are so constructedas to provide a considerably larger number of flexures than may beobtained with conventional clutch tubes, and which circular ends arepositively prevented from creasing under flexure.

And yet another object is to provide an inflatable tube of the typedescribed wherein the circular ends of the tube cross section are filledwith a non-inflatable O ring to provide a multiple function of (l)filling the internal cavity of the tube and thus reducing the air spacepresent when the tube is inactive and of (2) reinforcing the inner andouter periphery of the tube so that centrifugal force during use willnot tend to expand the tube or move it out of position, and of (3)preventing the extreme ends of the tube cross section from creasing andcausing rapid deterioration as would occur in an ordinary flat tube whencollapsed, and (4) providing a mandrel about which the sections arebuilt up in manufacturing the tube.

Another object of this invention is to provide an inflatable flexibleelongated cross-section tube having horizontal fillers installed on itsupper and lower surfaces to provide a substantially flat operating faceto further reduce the amount of air required to engage the clutch orother operating mechanism.

And yet another object of this invention is to provide a novel method ofmanufacturing the tubes of this invention.

The construction and operation of the novel tube of this invention willbe apparent from the following description together with theaccompanying drawings in which:

FIGURE I is a top plan view of the tube of this invention.

FIGURE II is a section along line 22 of FIGURE I when the tube isdeflated; and 7 FIGURE III shows the section of FIGURE II in an inflatedposition.

FIGURE IV is a section along the line 44 of FIG- URE I of anotherembodiment of the tube of this invention in a deflated condition whereinthe tube is used with a special 0 ring unit.

FIGURE V is the section of FIGURE IV when the tube is inflated, showinga special 0 ring unit in place.

FIGURE VI is a detail plan view of the unique 0 ring unit of theembodiment shown in FIGURES IV and V.

2,992,955 Patented July 18, 1961 FIGURE VII is a cross sectional viewtaken along the lines 7--7 of FIGURE VI.

FIGURE VIII is a plan view of the tube of FIGURE I at the first step inits method of manufacture.

FIGURE IX is a cross sectional view along line 9-9 of FIGURE VIH.

FIGURE X shows the section of FIGURE IX after the 0 rings have beenadded.

FIGURE XI shows the section of FIGURE X with a piece of flat cover inthe process of being installed to complete the bladder portion of thetube.

FIGURE XII shows the section of FIGURE XI after a layer of fabric hasbeen cemented in place about its periphery.

FIGURE XIII shows the section of FIGURE XII in the process of having anupper and lower filler and end covers installed.

FIGURE XIV shows the completed section of the tube of this inventionafter curing.

FIGURE XV is a plan view of the flat disk used in an alternate method ofmanufacture of the tube of this invention.

FIGURE XVI is a cross section taken along the lines 16- 16 of FIGURE XV.

FIGURE XVII shows the first step in the method of manufacture of thistube by placing two disks together,

and the cross section here corresponds to lines 17-17 of FIGURE XV.

FIGURE XVIII shows a second step in the method of I manufacture ofadding 0 rings.

FIGURE XIX shows a third step in the method of manufacture of adding endcovers.

FIGURE XX shows a fourth step in the method of manufacture of addingreinforcing fabric.

FIGURE XXI shows a fifth step in the method of manufacture and shows thecompleted tube assembly.

In the several figures like references indicate similar parts wherein5--5 represents generally the flat ring portions of my tube T as bearingsurfaces to contact parts of a clutch not shown, one of which portionshas spud 6 communicative with cavity 7 between the flat portions 5through which activating fluid may be introduced into and dischargedfrom the tube as desired. About the inner and outer diameters of theflat portions, enlarged flex sections 88 are integrally formed,preferably reinforced by suitable cord or fabric 9 to withstand desiredoperating pressures within the tube. Within the flex sections there areprovided circularly disposed cavities 10 of suitable sizes to provideflex section readily accommodative of the desired stroking of the tube Tin a clutch. 'Ihese cavities are but continuations of the extremelysmall substantially zero volume cavity 7 between the flat matingportions 11 of tube T.

0 rings 12 and 13 are introduced into circular cavities 10 duringmanufacture of the tube (see FIGURES X and XVIII) to effectively fillthese cavities and thus reduce the combined internal volume of tube T tosubstantially zero when the tube is in its initial or deflated conditionas shown in FIGURE II. These 0 rings 12 and 13 are of a cross section tosnugly fit cavities 10 when the tube in its deflated condition and in apreferred form also are larger than the central cavity 7 when the latteris expanded so that the 0 rings will not be dislodged out of theirrespective end cavities when the tube is inflated as shown in FIGURE HI.The 0 rings will materially improve the performance of the clutch tube Tby reinforcing the outer and inner circumference against centrifugalforce which may either weaken the material cross section or cause it tobe displaced from its normal operating position.

Spud 6 includes a hose or tube connecting means, in this case seen to beinternal threaded opening 6a thru which the activating fluid isdelivered into cavities 7 and 10 for convenience by way of channel 7awhich distributes the fluid within the tube. Prior to introduction ofpressurized fluid, the only cavity of elongated center members 5--5 ofthe tube T is the very small channel 7a (and a minute air clearancebetween the mating surfaces 11) which permits movement of the activatingfluid. Consequently the fluid volume of the tube when deflated isvirtually zero between the mating faces 11 and with the insertion ofrings 12 and 13 is substantially zero for the entire tube.

Another embodiment of this invention is shown in FIGURES IV and V tocomprise a tube T substantially similar to tube T but having a widercentral cavity 7 extending horizontally between circular end cavities 10for the purpose of receiving the unique 0 ring unit R shown in detail inFIGURES VI and VII. Unit R includes two 0 ring sections 12 and 13 and aninterconnecting horizontal strip 14 moulded integrally with the 0 ringsections into a continuous ring as shown in FIGURE VI. The advantages ofthis unit R over the two separate rings 12 and 13 are, firstly theconvenience of handling and storage of a single unit in place of twounits of different size and additionally the provision of an inner andouter ring of greater strength and resistance to deformation undercentrifugal force than separate single 0 rings of the same size.

The novel method of manufacture of the tube of this invention may beseen by reference to FIGURES VIII- XIV inclusive to comprise basicallythe following steps:

(1) Moulding an open face bladder 20 of flexible material (such asmbber, neoprene, plastics and the like) into the semi-C shape shown inFIGURES VIII and IX havingtwo sections adapted to receive 0 rings inposition.

(2) Inserting 0 rings 12 and 13 of flexible or nonflexible material intothe cavity 10 of bladder 20 as seen in FIGURE X. i

(3) Closing the open top gap 21 of bladder 20 by placing rubber cement22 on adjoining edges 23 of bladder 20 and a flat cover 24 (which is ofsimilar material to the bladder; in one case: gum rubber), afterconditioning both surfaces by roughenin'g to retain the cement, and thenpressing or rolling the adjoined surfaces to insure adhesion, thusforming a completed bladder 25 as shown in FIGURE XI.

(4) Covering the circumference of the bladder 25 with a reinforcingfabric 9 such as heavy loose mesh cloth (such as biased tire cord) asshown in FIGURE XII and cementing in place, and then curing the bladderby conventional vulcanizing methods, while suitable pressure ismaintained inside the bladder.

Adding end covers 26 and upper and lower fillers 28 as shown in FIGUREXIII and cementing all parts in place as in FIGURE XIV, and theninserting the tube in a furnace for its final curing under conventionalpressures and temperatures.

The steps of manufacture of the embodiment shown in FIGURES IV and V issubstantially identical to the first embodiment with the exception thatO ring unit R is substituted for 0 rings 12 and 13 in step (2) above.

An alternate method of manufacture is shown in FIG- URES XV-XXI, andconsists of the initial step of placing disks 30 and 31 together asshown in FIGURE XVII. The disks 30 and 31 are molded to an identicalshape, except that disk 30 only includes an opening 32 to re ceive aspud 6 (spud not shown in this view) as seen in FIGURE XVI.

After placing disks 30 and 3 1 as shown in FIGURE XVII, a pair of 0rings 12 and 13 are added at the end contours 33 which are shaped to thesame radius as the 0 rings.

The 0 rings 12 and 13 now act as a mandrel about which end covers 34 maybe wrapped as shown in FIG- URE XIX and cemented to the disks 30 and 31.

The next step is the covering of the assembly thus far with a loose meshmaterial such as biased tire cord 9 and cementing in place (as indicatedat 28 in FIG. XXI) in such a manner as to form a protective covering, asshown in FIGURES XX and XXI after which the assembly is cured.

The final step is the bonding of upper and lower fillers 35 to theassembly of FIGURE XX as shown in FIGURE XXI and curing the unvulcanizedportions of the complete assembly. It will be noted that the ends 36 offillers 35 may not be bonded to the outer surfaces of the end members 37in this embodiment to provide a tube with increased flexibility in theend members as more fully described in copending application Serial No.708,- 614, filed January 13, 1958.

It will be obvious without additional illustration that the 0 ring unitR can be used in place of Q rings 12 and 13 in the assembly shown inFIGURE XXI by a slight change in the procedure of manufacture, i.e.,placing the disks 30 and 31 on opposite sides of the horizontal strip 14as the first step in the manufacture of this tube assembly. It will alsobe understood that the fillers may be omitted from the outer faces ofthe parallel flat sections and correspondingly suitable contoursprovided in the faces of the clutch or brake mechanisms forcooperatively receiving the tubes.

From the foregoing description, it will be readily seen that there hasbeen produced a device which substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice, such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new anduseful, and upon which Letters Patent is desired:

1. The method of making an inflatable tube for clutches including thesteps of making a pair of flat unvulcanized disk sections having minorand major diameters one of which sections has a spud openingtherethrough, bringing the inner faces of the disc sections together,placing an O ring adjacent the respective minor and major diameters ofthe disc sections, bringing a flexible section of unvulca-nizedreinforced rubber around the 0 rings and ouring the unvuloanizedsections by vulcanization.

2. The method of making an inflatable tube for clutches comprising thesteps of forming an 0 unit with 0 rings of two diameters with aconnecting section therebetween, forming a pair of flat disks one ofwhich includes a spud opening, placing said disks on opposite sides ofsaid 0 unit, placing end covers around 0 rings and cementing said coversto said disks, forming reinforcing fabric about the outer circumferenceof said covers, placing a spud in said spud opening, and curing thediscs reinforcing fabrics and end covers.

3. The method of making an inflatable bladder, comprising the steps of:molding an open face bladder of flexible material into a semi-C shapehaving round end sections adapted to receive 0 rings, inserting 0 ringsinto said sections, cementing a flat cover over the top of the open faceof said bladder and enclosing an inner cavity forming an opening in thebladder, and inserting a spud through the opening to introduce fluidtherein for filling the inner cavity and inflating said bladder, andfinally curing the bladder inside a confining mold.

4. The method of making an inflatable bladder, comprising the steps of:molding an open face bladder of flexible material into a semi-C shapehaving round end sections adapted to receive an O ring unit, insertingan 0 ring unit into said sections, cementing a flat cover over the topof the open face of said bladder and enclosing an inner cavity, formingan opening in the bladder, and inserting a spud through the opening tointroduce fluid therein for filling the inner cavity and inflating saidbladder.

5. The method of making an inflatable tube for clutches and the likecomprising the steps of: molding an open face bladder of flexiblematerial into a semi-O shape having round end sections adapted toreceive 0 rings, inserting 0 rings into said sections, cementing a flatcover over the top of the open face of said bladder and forming an innercavity therein, forming 'an opening in the bladder, inserting a spudthrough the opening to introduce fluid therein for filling the innercavity, cementing a reinforcing fabric around the outer circumference ofsaid bladder, cementing end covers over the fabric at each end of saidbladder, cementing upper and lower fillers on the bladder between theend covers, and then curing the bladder, the covers and the fillers.

References Cited in the file of this patent UNITED STATES PATENTS2,251,444 Fawick Aug. 5, 1941 2,431,937 Hunter Dec. 2, 1947 2,460,168Oaserta Jan. 25, 1949 2,578,730 Nicholson et a1. Dec. 18-, 19512,612,909 Keller Oct. 7, 1952 2,666,007 Hovey Jan. 12, 1954 2,688,983Bowerman Sept. 14, 1954 2,762,737 Keller Sept. 11, 1956 2,805,744Cardwell et a1 Sept. 10, 1957 2,839,440 P'feiffer et a1. June 17, 1958FOREIGN PATENTS 644,516 Great Britain Oct. 11, 1950 529,664 Canada Aug.28, 1956

5. THE METHOD OF MAKING AN INFLATABLE TUBE FOR CLUTCHES AND THE LIKECOMPRISING THE STEPS OF: MOLDING AN OPEN FACE BLADDER OF FLEXIBLEMATERIAL INTO A SEMI-C SHAPE HAVING ROUND END SECTIONS ADAPTED TORECEIVE O RINGS, INSERTING O RINGS INTO SAID SECTION, CEMENTING A FLATCOVER OVER THE TOP OF THE OPEN FACE OF SAID BLADDER AND FORMING AN INNERCAVITY THEREIN, FORMING AN OPENING IN THE BLADDER, INSERTING A SPUDTHROUGH THE OPENING TO INTRODUCE FLUID THEREIN FOR FILLING THE INNERCAVITY, CEMENTING A REINFORCING FABRIC AROUND THE OUTER CIRCUMFERENCE OF